In any pneumatic tubing system, the installer must choose not only the pathway of the tubing, the radius of the bends, and airspeed, but also support. One can support the tubing by many means but sometimes the engineer needs to accommodate for a long span.
In cases when the object being conveyed is small (microfibers, caps, granules, etc) we recommend a rectangular tube section.
In order to transition the round to rectangular (for the span) and back to round, we have a process that is easy on the product.
When hanging the tubing over a long span, hang the rectangular tubing so that the minor axis (short side) is vertical.
Here are a few pics to show the point.
First, a 12′ span of 3″ round tubing. Notice the tube is supported on the minor axis. https://www.busada.com/blog/rectangular-tubing-bend-guide
And here is a 3″ OD round tube, notice the sag that will get worse in time.
Questions? Call us at the shop at 540-967-2882